Heterogeneity of Leaf-Level Photosynthesis as Seen Through the Lens of Ozone, Soybean, and Chlorophyll Fluorescence Imaging
type: CreativeWork
description: Leaf-level heterogeneity of photosynthetic CO2 assimilation occurs naturally in plants under stressed and non-stressed conditions and has been attributed in the past to stomatal heterogeneity. Variation in the biochemistry of mesophyll cells has been cited as another potential cause of photosynthetic heterogeneity, but there has been no work done to investigate the effects of biochemical heterogeneity. The biochemistry of C3 leaf photosynthesis under steady-state conditions is widely characterized in vivo by the Farquhar et al. (1980) model to interpret gas exchange data and in turn to model steady-state CO2 assimilation in leaves, canopies, landscapes and the globe. Understanding the effects of heterogeneity in the key biochemical parameters Vc,max (the maximum Rubisco carboxylation rate) and Jmax (the maximum rate of whole chain electron transport) on the validity of the Farquhar et al. (1980) model could be crucial to improving the existing models of plant productivity. One particular inducer of leaf-level photosynthetic heterogeneity is tropospheric ozone (O3), a phytotoxic air pollutant whose rising global background concentrations have been widely recognized as a problem affecting both natural communities and agricultural systems, especially plant species such as soybean (Glycine max). This thesis aims to further the present understanding of the effects of leaf-level biochemical heterogeneity in photosynthesis and advance the current ability to measure and analyze this heterogeneity. Modulated chlorophyll a fluorescence imaging (CFI) coupled with gas exchange was used to test the hypothesis that O 3 induces differential leaf-level spatial effects on photosynthesis in soybean depending on its exposure regime (acute vs. chronic). Spatial analytic techniques derived from the field of remote sensing were adapted to quantify the leaf-level spatial heterogeneity of photosynthetic processes within the leaf. The fluorescence imaging data revealed that the pattern and …
abstract: Leaf-level heterogeneity of photosynthetic CO2 assimilation occurs naturally in plants under stressed and non-stressed conditions and has been attributed in the past to stomatal heterogeneity. Variation in the biochemistry of mesophyll cells has been cited as another potential cause of photosynthetic heterogeneity, but there has been no work done to investigate the effects of biochemical heterogeneity. The biochemistry of C3 leaf photosynthesis under steady-state conditions is widely characterized in vivo by the Farquhar et al. (1980) model to interpret gas exchange data and in turn to model steady-state CO2 assimilation in leaves, canopies, landscapes and the globe. Understanding the effects of heterogeneity in the key biochemical parameters Vc,max (the maximum Rubisco carboxylation rate) and Jmax (the maximum rate of whole chain electron transport) on the validity of the Farquhar et al. (1980) model could be crucial to improving the existing models of plant productivity. One particular inducer of leaf-level photosynthetic heterogeneity is tropospheric ozone (O3), a phytotoxic air pollutant whose rising global background concentrations have been widely recognized as a problem affecting both natural communities and agricultural systems, especially plant species such as soybean (Glycine max). This thesis aims to further the present understanding of the effects of leaf-level biochemical heterogeneity in photosynthesis and advance the current ability to measure and analyze this heterogeneity. Modulated chlorophyll a fluorescence imaging (CFI) coupled with gas exchange was used to test the hypothesis that O 3 induces differential leaf-level spatial effects on photosynthesis in soybean depending on its exposure regime (acute vs. chronic). Spatial analytic techniques derived from the field of remote sensing were adapted to quantify the leaf-level spatial heterogeneity of photosynthetic processes within the leaf. The fluorescence imaging data revealed that the pattern and …
author: Chen, Charles P.
language: eng
keywords: Biology, Plant Physiology
date published: 2015-09-25T22:42:34Z
date modified: 2026-07-22T22:26:25Z
provider: University of Illinois - Urbana-Champaign
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Illinois at Urbana-Champaign

PropertyValue
property ID: Handle
value: http://hdl.handle.net/2142/85377